用于自旋-声子弛豫的多参考密度矩阵嵌入
Multireference Density Matrix Embedding for Spin-Phonon Relaxation
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中文总结 AI 辅助
研究自旋-声子弛豫，采用多参考密度矩阵嵌入框架，应用于多种单分子磁体和分子晶体，能在多参考水平处理磁中心配位球，减少计算量，将自旋-声子弛豫计算从孤立分子扩展到分子晶体。
中文摘要 AI 辅助
自旋-声子耦合控制着包括单分子磁体和分子自旋量子比特在内的众多系统中的磁弛豫。在大多数情况下，自旋弛豫率的准确预测需要多参考电子结构方法，但其计算成本很大程度上限制了此类计算仅适用于孤立分子。本文表明，自旋-声子弛豫率可在多参考密度矩阵嵌入框架内计算。我们将该方法应用于三个钴基和两个镝基单分子磁体以及一个钴基分子晶体。在所有系统中，仅在多参考水平处理磁中心的第一配位球就能重现自旋弛豫率，与非嵌入的CASSCF计算结果吻合良好，同时将相关问题减少到总基函数的10%-68%。周期性计算进一步表明，对于一个分子晶体，仅使用2569个总基函数中的259个嵌入活性空间就能计算出自旋弛豫率。这些结果表明，多参考密度矩阵嵌入将定量自旋-声子弛豫计算从孤立分子扩展到了分子晶体。
英文摘要
Spin-phonon coupling governs magnetic relaxation in numerous systems including single-molecule magnets and molecular spin qubits. In most cases, the accurate prediction of spin relaxation rates requires multireference electronic structure methods, but their computational cost has largely restricted such calculations to isolated molecules. Here we show that spin-phonon relaxation rates can be computed within a multireference density matrix embedding framework. We apply the approach to three cobalt- and two dysprosium-based single-molecule magnets and to a cobalt-based molecular crystal. Across all systems, treating only the first coordination sphere of the magnetic center at the multireference level reproduces spin relaxation rates in good agreement with non-embedded CASSCF calculations while reducing the correlated problem to 10-68% of the total basis functions. Periodic calculations further demonstrate that spin relaxation rates can be computed for a molecular crystal using an embedded active space of only 259 basis functions out of a total of 2569. These results show that multireference density matrix embedding extends quantitative spin-phonon relaxation calculations from isolated molecules to molecular crystals.
